Linear bus topology features, advantages, and disadvantages
A bus or linear bus topology is a type of computer network layout where all devices are connected to a single cable called the linear bus. The cable is also called a backbone or trunk. Bus cable is shared by the devices and allows data to flow in both directions. All devices have an equal chance to transmit data and they keep checking for any message addressed to them.
The main characteristics of bus topologies are that it has a main bus cable where all devices are connected and a terminator at each end of the cable. Bus topology advantage is that it is simple to add a new device to the network and failure of one doesn’t affect others. However, if the main bus cable fails the whole network fails.
Table of Contents
Architecture/layout of bus topology diagram
To create a linear bus topology you will require hardware such as bus cable, terminator, and devices to be connected to the network. The most common cable used for the backbone is coaxial, while those connecting to individual computers can be twisted pairs.
How devices communicate in a bus topology
When any computer is ready to communicate it broadcast the message to the linear cable. The signal travel in both direction. All devices on the network will check the message address.
If the message is not addressed to them they will ignore it. If the address matches theirs, it will pick up the message from the cable and interpret it appropriately. The main challenge with broadcasting is data collision when two signals meet on the main cable.
Features/ characteristics of bus
- Main bus cable or linear bus: the layout has one main cable where all devices on the network are connected.
- Terminators at each end of the main cable. Terminators are used at the end of the cable to prevent signals from reflecting back along the signal. This help reduces signal distortion and interference.
- Signal collision: since all computers on the network share the same medium for transmission there are cases of signal collision. This degrades the network.
- Broadcast communication: a device that wants to communicate broadcasts the message to the linear bus and the destination device picks it up from there.
Advantages linear bus
- Simple to set up: A linear bus topology is simple to set up and maintain compared to other types of topology layouts.
- It is cost-effective. The topology is cheaper to set up compared to the star layout. It requires fewer networking components to establish a network.
- It requires less cabling compared to topologies like star or mesh topologies.
- Simple to add a new device: to expand the network you just need to tap on the trunk cable and you are good to go.
- If one device fails it doesn’t affect the operation of others.
Disadvantages of bus network topology
- Difficult to troubleshoot cable: When the bus cable has a problem it is very hard to identify specifically where the problem is.
- Suitable for a small network. As the network grows it becomes inefficient since all those devices are sharing the same media. The cable creates a bottleneck in data transmission and speed.
- Failure of the backbone cable affects the entire network.
- Due to sharing of cable and broadcasting signal the topology is not secure compared to other layouts.
- The network requires terminators at each end of the cable.
- Signal collision. Due to sharing of cable, there are high chances of signal colliding which degrade the network.